After spending much time configurating znc on OpenWrt with the helps from people on znc channel, I believe I have a pretty decent configration, and would like to suggest the following modifications to the znc package so other people can benefit from it.
Drop UCI config, and use znc's config directly.
With UCI config, it means the used config dir is temporary, and it makes modules like webadmin less useful. Also it makes remembering password for the sasl module very hard, which doesn't support specifying the password when loading the module. The same goes for using a pem file for the cert module and making it stick.
I know the znc package currently supports external config. But the problem is that the pid file is specified to live in /tmp/etc/znc/znc.pid. I'm not sure if this directory will be created when the external config is used. Ideally, it should live in /var/run/znc/znc.pid with /var/run/znc be owned by a limited user znc (more on this later).
Use sudo instead of su
U